More to the point, firearms have been a fact of life in the US since it was founded. Almost everyone who has one knows what the rules are, and how to behave with them

An unfortunately large number of people are buying AR drones and dji phantoms, and doing stupid shit with them. Luckily some of that can be dealt with sensibly, like the idiot in new york late last year who was bouncing an ar drone off buildings for a while, before crashing it into a crowded sidewalk. New york police tracked down the operator and charged him with something like reckless endangerment or somesuch.

Someone got in trouble here in NZ a while ago. Had bought a drone, flew it through a downtown area, between the hospital (active helipad) and the Airport (controlled airspace). when the CAA and the police tracked him down, he didn't even know there were any rules he had to comply with.

the .5 channel is usually a marketing claim to the effect that the helicopter can move in a direction you don't have a control for.

eg: a 2.5 channel helicopter may have throttle and rudder, allowing it to climb, sink, and turn left and right. And the helicopter might be trimmed with an offset tail rotor such that in a left turn, it pirouettes on the spot, and in a right turn it moves forward.

2 channel is usually throttle and rudder
3 is usually throttle, rudder and a pusher-prop
4 is usually throttle, rudder and cyclic (elevator and aileron)
5 is throttle, collective, rudder and cyclic